My research activities are centered in the area of experimental relativistic heavy ion physics. Its primary goal is the study of the properties of nuclear matter under extreme conditions of several trillion kelvin temperature, in which quarks and gluons become locally deconfined. This so-called "Quark-Gluon Plasma" (QGP) is predicted to have existed about one microsecond after the Big Bang.

The observation of a strong collective flow behavior at the Relativistic Heavy Ion Collider (RHIC) suggested the formation of a strongly coupled Quantum Chromodynamics (QCD) state of matter that exhibits close-to-zero shear viscosity to entropy density ratio, consistent with an almost ''perfect liquid''. The onset of the LHC is bringing a "COBE-to-WMAP" paradigm shift to the field of heavy ion physics. With a variety of new probes and tools, the next goal is to quantitatively characterize the properties of QGP and pin down the origin of this strongly coupled QCD liquid. This research will shed light on the fundamental dynamics of confinement phenomena emerging in strong force, which is still an unresolved problem from first principle QCD.

High-Density Proton-Proton Physics

Quantum Chromodynamics (QCD) is the theory that describes the strong interactions between quarks and gluons making up hadrons. The advent of the Large Hadron Collider (LHC) brings QCD to a new testing ground, accessing the energy scale beyond TeV level, probing proton structure down to extremely small x and at extreme particle density.

I have a strong interest in the very high-particle-density (high multiplicity) proton-proton interactions. In 2010, the first unexpected phenomena in proton-proton collisions at the LHC was reported by the CMS collaboration during a special seminar at CERN and a paper entitled "Observation of Long-Range Near-Side Angular Correlations in Proton-Proton Collisions". It was thought that QGP could only be created in large nucleus-nucleus collisions, but this observed characteristic ``ridge-like'' structure in multiparticle correlations for high-particle-density pp collisions provided the first clear evidence of collective effects in pp collisions, and also has the promise of uncovering a deeper internal structure of the proton and studying the quantum fluctuations that occur there. It opens up a new avenue in the exploration of the nature of the strong force in a nonperturbative regime using a tiny but high density quark and gluon system. With future upgrade of the LHC and CMS detector, these high multiplicity pp events will be investigated in great detail and shed more light on the QCD physics in the very high-density regime.